diff --git a/src/04-constants.go b/src/04-constants.go
new file mode 100644
index 0000000..f9647ce
--- /dev/null
+++ b/src/04-constants.go
@@ -0,0 +1,19 @@
+package main
+
+import (
+  "fmt"
+  "math"
+)
+
+const s string = "this is a constant"
+
+func main() {
+  fmt.Println(s)
+
+  const n = 500000000
+  const d = 3e20 / n
+
+  fmt.Println(d)
+  fmt.Println(int64(d))
+  fmt.Println(math.Sin(n))
+}